Crankshaft pulley(timing) failure

[Tesa]

Hello,

on this weekend I had a crankshaft pulley failure, engine stopped at the same time. Unfortunately it was on hard pull. When I came home on rope, I tried to found what happened. There are few pictures from endoscope (but its a cheap unit from DX so the pictures arent good.

Could you guess if intake valves touched the piston, or not ? It seems that yes, but all 10 ? Its a very strange that there is no mark from exhaust valves...

Im a little pissed off, believe me.

Pictures from all 5 cylinders :


























Radek

[UrS4boy]

When the cam timing belt snaps or otherwise stops turning the cams, then one cylinder will have had its intake valves stuck out too far and will have been hit by the pistons which are still going up and down (unless you got the engine off and clutch in immediately (which is doubtful)). As a result, two intake valves will be bent, ever so slightly. Because of the valve angles, the exhaust valves almost never get hit by the pistons, even when stuck all the way out when the cam belt snaps/stops driving the cams.

Sorry to say it, but you are going to have to remove the head and replace at least 2 intake valves. On the upside, you get to replace the guides and seals on all the valves while the head is off and install a new all metal headgasket (if you didn't have one already). Oh, yeah, and do a timing belt Re and Re.

[Tesa]

Its bad, because engine has been rebuilt before 30 000km

[filip.krticka]

Could you tell me who did this rebuilt. If you need stock spistons and conrods I have one set from my engine.
What was wrong with your crankshaft pulley?

[Tesa]

Hello Filip,

thank you for your interest. It seems that there wont be any massive destroyment, but I will see when I remove head. The conrods are uprated and rated to 650+hp. It also seems, that pistons are okay, only small marks from inlet valves. But I will see more after dissasembling.

The rebuild was done in Croatia 3 years ago by man which I trust.

There is a allen-wood key on crankshaft timming pulley which cracked. And timming went wrong. You can find thread here about this non-common issue.

Radek

[UrS4boy]

The rebuild was done in Croatia 3 years ago by man which I trust (rs200). There is a allen-wood key on crankshaft timming pulley which cracked. And timming went wrong. You can find thread here about this non-common issue.
Radek

I guess you don't post here often Radek. Cracking the toothed crank pulley on these 20VT engine is common, especially if the person doing the timing belt replacement uses an impact wrench to remove or install the crank bolt. Documented many times. Common issue. You might want to talk to your man in Croatia.

[Tesa]

I guess you don't post here often Radek. Cracking the toothed crank pulley on these 20VT engine is common, especially if the person doing the timing belt replacement uses an impact wrench to remove or install the crank bolt. Documented many times. Common issue. You might want to talk to your man in Croatia.

My english is not so good, I meant its a known issue, but its not that common that you can meet it on every engine.

[filip.krticka]

UrS4boy: and vag tool for tightening is required...

[filip.krticka]

Radku,
myslí tím použití rázové utahovačky. A nevím jak jste to utahovali, ale bez přípravku přes převodovku to není ok. Dali jste nové ozubené kolo?

[Thuppu]

Next time, use a CrMo pulley. http://speed-autoteile.fi/index.php?...&product_id=78

[UrS4boy]

UrS4boy: and vag tool for tightening is required...

The VAG crank lock too IS required but the VAG tool for tightening the nut is just an extension so you can use a smaller torque wrench if you don't have one that goes to 338 lb-ft (460 Nm) (with a 3/4" (19mm) drive 27 mm socket). The extension allows you to use a torque wrench that only goes to 258 lb-ft (350 Nm).

[Tesa]

Filip :
bylo to utaženo přípravkem a použítím velké gola sady na 200Nm + 180°. Kolo bylo použito nové. Prostě smůla, ale to se stává

I have already contacted Volcano RS about crankshaft pulley, so I will order it from him. I have also found some thread regarding VAG crank lock tool, so I will make one for my usage.
During week I will remove head and see how massive are the damages to the valves + seats.

Radek

[rs200]

I'm that man from Croatia who did this engine before 3 years. it was my engine, in my audi 200 20v, before it go to Tesa's car.

of course that I have cranking tool for pulley. it is not OEM from audi , they are home made for 3B engine pulley from steel. where is the problem?
I use Loctite glue for bolts every time. before 3 years I bought new one timming belt pulley .
here is the picture of it - 05.11.2009.



last time I touch crank bolt it was when I change everithing from 3b to aan .



it is definetly that I'm guilty for that, in some % because there in no other person who did something on engine. only me ! but I built that engine for my self, not for sale..
I will help Radek to fix the problem. we are still in contact every day.

[Rusty]

Unfortunately, even new ones of these fail. It's been documented in various threads on here over the years It's not really anyone's fault other than Audi for makeing a part that either stress fractures or is too brittle for the purpose it was designed for

[UrS4boy]

I'm that man from Croatia who did this engine before 3 years. it was my engine, in my audi 200 20v, before it go to Tesa's car.

All I meant with "You might want to talk to your man in Croatia" was Tesa should contact the fellow in Croatia and ask him about his technique to tighten the crank bolt, i.e. did he use the VAG tools or did he just use an impact wrench.